title: A new fluorescence turn-on assay for trypsin and inhibitor screening based on graphene oxide.
abstract: In this paper, we describe a new continuous fluorescence turn-on method for trypsin assay and inhibitor screening in situ. This assay is designed based on the following assumptions: (1) It is expected that the fluorescein-labeled peptide composed of six arginine residues (Arg(6)-FAM) with positive charges will interact with the negatively charged edge of water-soluble graphene oxide (GO) because of electrostatic interactions to form a GO/Arg(6)-FAM complex. As a result, the fluorescence of fluorescein will be quenched because of the energy transfer from fluorescein to GO. (2) Arg(6)-FAM can be hydrolyzed into small fragments in the presence of trypsin, and accordingly, the GO/Arg(6)-FAM complex will be dissociated, gradually leading to fluorescence recovery for the solution. In this way, the trypsin activity can be easily assayed with the ensemble of Arg(6)-FAM and GO. Additionally, the ensemble can be employed for screening of the inhibitors of trypsin.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Xinggui
authors.initials: X
authors.lastname: Gu
authors.forename: Ge
authors.initials: G
authors.lastname: Yang
authors.forename: Guanxin
authors.initials: G
authors.lastname: Zhang
authors.forename: Deqing
authors.initials: D
authors.lastname: Zhang
authors.forename: Daoben
authors.initials: D
authors.lastname: Zhu
mesh_terms: D004353:Drug Evaluation, Preclinical / Q000379:methods*; D019793:Fluorescein / Q000378:metabolism; D005453:Fluorescence; D006108:Graphite / Q000378:metabolism*; D010087:Oxides / Q000378:metabolism*; D013194:Staining and Labeling / Q000379:methods; D014357:Trypsin / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D010087:Oxides; D014361:Trypsin Inhibitors; D006108:Graphite; D014357:Trypsin; D019793:Fluorescein